
	                //图片上传预览    IE是用了滤镜。
	        function previewImage(file)
	        {
	          var MAXWIDTH  = 100;
	          var MAXHEIGHT = 100;
	          var div = document.getElementById('preview');
	          if (file.files && file.files[0])
	          {
	              div.innerHTML ='<img id=imghead>';
	              var img = document.getElementById('imghead');
	              img.onload = function(){
	                var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
	                img.width  =  rect.width;
	                img.height =  rect.height;
	//                 img.style.marginLeft = rect.left+'px';
	                img.style.marginTop = rect.top+'px';
	              }
	              var reader = new FileReader();
	              reader.onload = function(evt){img.src = evt.target.result;}
              reader.readAsDataURL(file.files[0]);
	          }
	          else //兼容IE
	          {
	            var sFilter='filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="';
	            file.select();
	            var src = document.selection.createRange().text;
	            div.innerHTML = '<img id=imghead>';
	            var img = document.getElementById('imghead');
	            img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
	            var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
	            status =('rect:'+rect.top+','+rect.left+','+rect.width+','+rect.height);
	            div.innerHTML = "<div id=divhead style='width:"+rect.width+"px;height:"+rect.height+"px;margin-top:"+rect.top+"px;"+sFilter+src+"\"'></div>";
	          }
	        }
	        function clacImgZoomParam( maxWidth, maxHeight, width, height ){
	            var param = {top:0, left:0, width:width, height:height};
	            if( width>maxWidth || height>maxHeight )
	            {
	                rateWidth = width / maxWidth;
	                rateHeight = height / maxHeight;
	                 
	                if( rateWidth > rateHeight )
	                {
	                    param.width =  maxWidth;
	                    param.height = Math.round(height / rateWidth);
	                }else
	                {
	                    param.width = Math.round(width / rateHeight);
	                    param.height = maxHeight;
	                }
	            }
	             
	            param.left = Math.round((maxWidth - param.width) / 2);
	            param.top = Math.round((maxHeight - param.height) / 2);
	            return param;
	        }